Another way is to take a small file and file a notch into the backside of the nock. When you are almost through, a pair of needle nose pliers will be able to easily twist the nock open and off.

BE CAREFUL YOU DON'T FINE INTO YOUR SERVING OR WORSE YET YOUR STRING.

BTW: The facny pliers are the best way of doing it unless you like to stab yourself with the screwdriver